Stacked bellows and apparatus and method for manufacturing the same

ABSTRACT

An annularly seamless stacked bellows formed from a metal tube by initially forming convolutions in the tube in a die and crimping the outer edge of each convolution individually while in the die. The convolutions are sharp rolled at their inner edges and then compressed axially to form the seamless stacked bellows.

Mite Pantill es tat 1 STACKlED lBElLlLOWS AND APPARATUS AND METHOD FOR MANUFACTURING THE SAME [75] Inventor: HarryPanfill, Los Angeles, Calif.

[73] Assignee: Master Products Manufacturing (30., Los Angeles, Calif.

[22] Filed: Jan. 25, 1971 {21] Appl. No.: 109,695

Related U.S. Application Data [62] Division of Scr. No. 697,058, Jan. 11, 1968,

abandoned.

[52] US. Cl. 72/59, 113/116 BB [51] int. Cl 821d 15/06 [58] Field of Search 72/58, 59, 61, 62; 1 13/1 16 BB [56] References Cited UNITED STATES PATENTS 3,277,927 10/1966 Schneider 138/121 2,306,018 12/1942 Fentress 72/59 2,773,538 12/1956 De Mers 72/59 2,756,804 7/1956 Schindler et a1... 72/59 2,825,387 3/1958 Alltop et a1 72/59 1,879,663 9/1932 Dreyer 72/62 2,929,345 3/1960 Zatyko, Sr.. 72/58 X 1,980,264 1 1/1934 Giesler 72/59 3,067,799 12/1962 Cooper et a1. 72/59 3,326,091 6/1967 Allen 72/59 X Primary ExaminerRichard J. Herbst Attorney-Huebner & Worrel 57] ABSTRACT An annularly seamless stacked bellows formed from a metal tube by initially forming convolutions in the tube in a die and crimping the outer edge of each convolution individually while in the die. The convolutions are sharp rolled at their inner edges and then compressed axially to form the seamless stacked bellows.

2 Claims, 23 Drawing Figures PATENTEUJAR I am SHEEF 10F 8 INVENTOR. .AIIQERV pH/VF/LL.

PATENTEDJAH I I974 sum 2 0F 8 INVENTOR. HQREY .pflNF/LL.

1 STACKEI) BELLOWS AND APPARATUS AND METHOD FOR MANUFACTURING THE SAME This application is a divisional application of Ser. No. 697,058, filed Jan. 11, 1968, now abandoned.

BACKGROUND OF THE INVENTION This invention relates generally to a stacked bellows, and, more particularly, to a stacked bellows which is formed from a metal tube by a method and apparatus which permit the convolutions of the bellows to be formed automatically and continuously.

Metallic bellows have been utilized for a number of years as fluid conduits, hermetic seals, joints and couplings in applications where flexibility is required. For example, bellows'have been employed as conduits in the wings of aircraft wherein it is necessary that the conduits be flexible to accommodate movement of the wings and temperature variations. Generally speaking, there have been two types of bellows available, namely, formed bellows and stacked bellows.

Formed bellows are conventionally manufactured by surrounding a metal tube with a die having an annular channel therein, and by exerting an axial force upon hydraulic fluid in the tube to deform the wall thereof into the channel of the die to form each convolution of the bellows. This method has several limitations. For example, since high hydraulic pressure is required to deform a metal tube in such a method, often leaks occur in the forming apparatus, thereby requiring that the apparatus be shut down to replace sealing rings and to remove hydraulic fluid from the surface of the various parts of the apparatus. In addition, due to the limitations of hydraulic pressure which may be employed in such a method, it is impractical if not impossible to deform a metal tube into a die channel having a sharp outer periphery, which would be desired in order to produce bellows having convolutions with sharp outer edges. It is for this latter reason that formed bellows available on the market today have convolutions with rounded inner and outer edges. Such bellows are restricted' in their usefulness due to their lack of flexibility, being capable of only about percent axial and radial movement. Finally, the use of hydraulic fluid in forming bellows is disadvantageous if the bellows is formed of two layers, that is, one produced by simultaneously deforming two concentric metal tubes. If a break were to occur in the inner tube-during the forming process of such a bellows, hydraulic fluid would leak through the break into the space between the inner and outer tubes of the bellows. When such a bellows is employed as a conduit, the hydraulic fluid existing between the layers of the bellows could leak out of the defective area of the inner tube into the flow path through the bellows, causing contamination of the fluid passing therethrough.

Because of the aforementioned limitations of formed bellows, stacked bellows are often utilized. Stacked bellows are conventionally manufactured by stamping out annular plates from metal sheets, welding or soldering the outer annular edges of pairs of the plates to form separate convolutions and welding or soldering the inner annular edges of each convolution so formed to the inner edges of adjacent convolutions to produce a series of convolutions. Such bellows have the advantage that the annular plates are closable in stacked relationship due to the sharp edges provided at the inner and outer peripheries of the convolutions of the bellows. In fact, stacked bellows formed in this manner are capable of about percent greater axial and radial movement than are the formed bellows discussed above. However, as can be readily appreciated, the process of stamping out annular plates and welding or soldering them together to form a stacked bellows is time consuming and expensive. In addition, leakages often occur in stacked bellows formed in this manner due to corrosion resulting from changes in grain structure in the metal occurring at the annular seals of the bellows. Also, cleaning fluids which are used on stacked bellows after the welding or soldering operations sometimes become trapped in the annular seals of the bellows, thereby providing a source of contamination for fluid which passes through the bellows when used as a conduit.

While one might except that the conventional formed bellows could be axially compressed to produce convolutions which have sharp inner and outer edges like a stacked bellows, such is almost impossible due to the substantial amount of material existing at the outer and inner edges of the convolutions between the annular walls thereof, and particularly when the bellows has a large number of convolutions.

Therefore, what is desired is a means for inexpensively producing stacked bellows but without employing welding or other metal joining techniques.

While the term stacked bellows normally refers to a bellows formed by welding or soldering a series of annular plates together in the manner described above, it is to be understood that hereafter in this specification and claims, the term stacked bellows shall means broadly a bellows in which the inner and outer peripheries of the walls of the convolutions thereof converge together to sharp circular edges, with the walls closely adjacent, thereby providing a highly flexible conduit.

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide an annularly seamless stacked bellows.

Another object of the invention is to provide a stacked bellows which is produced by forming a metal tube rather than by welding or soldering annular plates together, as is the conventional practice in manufacturing stacked bellows.

A further object of the invention is to provide a stacked bellows which is formed without the use of welding or other metal joining techniques, and which has a high degree of both axial and radial movement, yet is free of corrosion areas as exist in conventionally formed stacked bellows.

Still a further object of the invention is to provide a method and apparatus for manufacturing stacked bellows in which a series of convolutions are automatically formed in a metal tube and individually crimped in a sequential manner.

According to the principal aspect of the present invention, there is provided an improved stacked bellows and a method and apparatus for manufacturing the same in which a metal tube is deformed into the shape of a stacked bellows rather than a series of annular plates welded together as has been the conventional practice. The stacked bellows formed in accordance with the present invention has all of the desired physical characteristics of the conventional stacked bellows, that is, ability to move substantially in either the axial or radial direction, and also the advantage of formed bellows of being capable of inexpensive manufacture and free of corrosion and leaks which often occur in the conventional stacked bellows.

The stacked bellows of the invention is formed by an apparatus which generally comprises a die having a bore therethrough in which the metal tube that is to be deformed is slidably positioned. An annular channel opens into the wall of the die bore. The die comprises basically two parts, each of which includes an annular wall of said die channel. One of the die parts is split or divided into two sections so as to be movable laterally away from the tube passing through the die. Initially a force is applied within the tube to force the wall thereof into the die channel to provide a single convolution in the tube. Thereafter, one of the die parts is moved axially toward the other to crimp the outer portion of the convolution. Then, the two sections of the split die part are moved laterally away from the metal tube being formed and the tube is advanced to a position so that the crimped convolution lies beyond the die and the next convolution forming step may be commenced. Since each convolution formed in the metal tube is crimped individually adjacent to its outer edge during the forming process, a bellows having a series of such convolutions may be axially compressed, after sharp rolling the inner edges of the convolutions, so as to form convolutions in the final product having generally the same configuration as a conventional stacked bellows, yet without the necessity of employing welding or other metal joining techniques.

Other objects, aspects and advantages of the invention will become apparent from the following description made in connection with the accompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of the tube forming portion of the apparatus of the invention;

FIG. 2 is a top elevational view of the tube forming portion of the apparatus;

FIG. 3 is a top elevational view, partially in section, of the tube supporting frame shown attached to the rear section of the tube forming portion of the apparatus;

FIG. 4 is a vertical section taken along line 4-4 in FIG. 2;

FIG. 4a is a horizontal section taken along line 4a4a in FIG. 4, showing a coupling used in the apparatus;

FIG. 5 is a vertical section taken along line 5-5 in FIG. 3;

FIG. 6 is a vertical section taken along line 6-6 in FIG. 3;

FIG. 7 is a horizontal section taken along line 77 in FIG. 4, showing a portion of the tube advancing mechanism of the invention, with the drive member thereof being shown in partial horizontal section;

FIG. 7a is a vertical section taken along line 7a-7a in FIG. 7, with the drive member being shown in partial vertical section through the shaft holding means thereof;

FIG. 8a is a top elevational view of a modified form of the drive means for the tube advancing mechanism of the invention;

FIG. 8b is a side elevation of the modified form of the drive means;

FIG. is a vertical section taken along line 8c-8c of FIG. 8b;

FIGS. 9-15 are enlarged fragmentary sectional views of the die and forming portions of the apparatus, illustrating the various parts and their positions during the sequence of steps performed by the apparatus;

FIG. 16 is a longitudinal sectional view of a bellows in the state formed by the apparatus illustrated in FIGS. 1-15;

FIG. 17 is a schematic showing of an apparatus for sharp rolling the inner edges of the convolutions of the bellows illustrated in FIG. 16, the latter being shown in longitudinal section;

FIG. 18 shows schematically the final compression step applied to the bellows, the latter being shown in partial longitudinal section; and

FIG. 19 shows the completed stacked bellows, partially in section, made in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, wherein like reference characters designate like or corresponding parts throughout the various views, there is shown in FIGS. l-7a the preferred embodiment of the apparatus of the present invention, generally designated 10. The apparatus comprises a base 12 having two upright end plates 14 and 16 secured thereto. The end plate 14 has a bore 18 therethrough coaxial with a bore 20 in the end plate 16. A fluid cylinder 22 is connected by means of posts 24 to the end plate 16.

As is well known in the art, a fluid cylinder is a device comprising a cylinder with a piston slidable therein. Ports are provided in the wall of the cylinder on opposite sides of the piston so that fluid supplied under pressure to either side of the piston causes movement of the piston in the desired direction. The actuating fluid may be either liquid or gas, providing either a hydraulic or pneumatic operated cylinder, respectively. A rod connected to the piston passes through the end wall of the cylinder for connection to the element which is desired to be moved. It is to be understood that the fluid cylinders referred to herein are made up of the same basic parts, function in the same manner as just described, and differ only in the actuating fluid employed.

The cylinder 22 is preferably a hydraulic cylinder. The piston rod 28 of the cylinder 22 is connected through a coupling 30 to a horizontal shaft 32 which passes through the bore 20 in the end plate 16. The shaft 32 extends into a bore 33 of a die, generally desig nated 34, mounted adjacent to the end plate 14, as best seen in FIGS. 9-15. An annular channel, generally designated 35, opens into the wall of the bore 33. A second shaft 36, which is coaxial with the shaft 32, passes through the bore 18 in the end plate 14, and into the bore 33. The shaft 36 is supported by a frame, generally designated 38, which is mounted to the right of the end plate 14, as seen in FIG. 3.

The frame 38 is supported by two vertical posts 40 and 42, only the tops of such posts being seen in FIG. 3. The bottoms of the posts 40 and 42 are supported by the floor, not shown. The frame 38 includes a series of four plates 44, 46, 48 and 50 welded to horizontal, parallel rods 52 and 54. The plate 46 has an annular boss 47 rotatably mounted within a horizontal bore 49 in the post 42. The plate 50 is welded to the end of the shaft 36, and includes a circular boss 56 which is journalled for rotation within a horizontal bore 58 in the post 40. The plates 44, 46 and 48 have central bores therein 60, 62 and 64, respectively, which are coaxial with the shaft 36, and are sufficiently large to receive therethrough a metal tube 66 after it has been worked into the form of a stacked bellows by the apparatus. The tube is preferably formed of annealed stainless steel.

The tube 66 is initially positioned in the apparatus with its right end, looking at FIG. 3, extending beyond the right side of the die 34. The shaft 36 of the frame 38 supports the right end of the tube while the left end of the tube, looking at FIGS. 1 and 2, is supported by shaft 32.

As best seen in FIGS. 3 and 6, the rods 52 and 54 of the frame 38 extend outwardly from the plate 44 toward end plate 14 and terminate in bayonet locking elements 68 and 70. The elements 68 and 70 are engaged in arcuate grooves 72 and 74, respectively, formed in a circular plate 76 welded to the end plate 14. The plate 76 has a central bore 78 extending therethrough which is coaxial with the bore 18 in the end plate 14.

When it is desired to insert a tube 66 into the apparatus or to remove the bellows formed therefrom, the frame 38 is rotated in the counterclockwise direction when looking at FIG. 6, to release the bayonet locking elements 68 and 70 from the grooves 72 and 74, respectively. The frame is then shifted away from the end plate 14 so that a bellows may be removed from the shaft 36, or a tube mounted onto the shafts 32 and 36.

Referring now to FIG. 10, there is positioned between the ends of shaft 32 and shaft 36 an element 80 which is formed of a resilient material such as natural rubber. The element 80 is axially aligned with the channel 35 in the die 34. Since the shaft 36 is fixed axially by means of the connection of the frame 38 to the plate 76, when the shaft 32 is moved by the hydraulic cylinder 22 toward the shaft 36, an axial force is applied against the sides of the element 80. This causes the element to expand radially, exerting a lateral force upon the inner wall of the tube 66, thereby forming the tube into the channel 35 of the die and forming a convolution 81 in the tube, as seen in FIG. 11.

FIG. 4a shows in detail the construction of the coupling 30 which connects piston rod 28 to shaft 32. The coupling includes an internally and externally threaded sleeve 30a which is engaged on the threaded end 32a of shaft 32 and on a threaded reduced diameter end section 280 of piston rod 28. The rod 28 has an annular shoulder 28b adjacent to the end section 28a which, in the position shown, abuts an annular shoulder 30b at the end of a recess 300 in sleeve 30a. A nut 30d locks the shaft 32 in position in the sleeve 30a. By loosening the nut 30d and rotating the sleeve 30a, the position of the end of the shaft 32 which contacts the resilient element 80 may be adjusted as desired; the sleeve 30a provides a relatively large range of adjustment of the axial positioning of such shaft.

A sleeve 31, split longitudinally along one side and threaded on its inner surface, engages the externally threaded sleeve 30a. As seen in FIG. 4, flanges 31a and 31b extend outwardly from the free ends of the split sleeve 31. A bolt 31c serves to draw the flanges together to tightly clamp the split sleeve 31 on the sleeve 30a. It can be seen that when cylinder 22 is actuated to move piston rod 28 toward the die 34, the stroke of the piston rod will be determined by the position of the split sleeve 31 with respect to the end plate 16, since the sleeve will abut the end plate. Thus, by adjusting the position of the sleeve 31 on sleeve 38a, the operator can control the stroke of the piston rod 28 and, hence, the force exerted upon the resilient element by shaft 32.

As seen in FIGS. 9-15, the die 34 comprises basically a first part 82, and a second part generally designated 84. The part 84 is divided into two separate sections 86 and 88, which may be referred to as die gates. The die gates are slidable laterally with respect to the longitudinal axis of the tube 66 in horizontal channels 90 and 92 fixed to the end plate 14. The gates have opposed flat surfaces 94 and 96 which mate at a vertical plane passing through the longitudinal axis of the die 34 when the gates abut one another as seen in FIG. 5. The die gates also have arcuate inner surfaces 98 and 100 and arcuate inwardly extending lips 102 and 104, respectively. When the mating surfaces 94 and 96 of the die gates 86 and 88 abut one another as shown in FIGS. 5 and 10, the arcuate surfaces 98 and 100 provide a continuous cylindrical surface, generally designated 103, which is spaced from the tube 66 while the arcuate lips 102 and 104 of the die gates provide an annular flange, indicated at 105, having an inner surface 105 which engages the outer surface of the tube 66.

A mechanism, generally designated 106, is provided for moving the die gates 86 and 88 toward and away from one another in the channels 90 and 92. Such mechanism includes two toggle arrangements 108, connected between the end plate 14 and the die gates. Since the construction of the two toggle arrangements is identical, only one will be described. The toggle arrangement includes a first pair of toggle arms pivotally connected at one end to end plate 14 by means of a vertical pin 112 rotatably mounted in a vertical bore 114 in a block 116 bolted to the end plate. A vertical pin 117 is journalled in the other ends of the arms 110 and in one end of a second pair of toggle arms 118, so that the two sets of toggle arms are pivotally mounted to the pin 117. The other end of the toggle arms 118 is pivotally conncted to the die gate 88 by means of a vertical pin 126 journalled in a horizontal bolted projection 127 of the gate and in the ends of the arms 118. A collar 124 disposed between the toggle arms 110 embraces the rod 117.

Four horizontally extending parallel posts 128, 130, 132 and 134 are fixed to the two end plates 14 and 16 of the apparatus. The mechanism 106 for laterally moving the die gates 86 and 88 includes two fluid cylinders 136 and 138, best seen in FIG. 2, which are preferably pneumatic actuated. The cylinder 136 is pivotally mounted by a pin 140 to a bracket 142 mounted to the posts 132 and 13.4 by means of a vertical brace 144. The cylinder 138 is pivotally mounted by means of a pin 146 to a bracket 148 which is fixed to a vertical brace 150 attached to the posts 128 and 130. The piston rod 152 of the cylinder 136 is connected to the collar 124 of the toggle arrangement 108 connected to the die gate 88, while the piston rod 154 of the cylinder .138 is connected to the corresponding collar of the toggle arrangement connected to the die gate 86.

When the piston rods 152 and 154 of the pneumatic cylinders 136 and 138, respectively, are in the position as illustrated in FIG. 2, the die gates 86 and 88 are open that is, in the position as illustrated in FIG. 9,

wherein the arcuate lips 102 and 104 are spaced from the outer surface of the metal tube 66.

When the cylinders 136 and 138 are actuated so that the pistons 152 and 154 move in a rightward direction as viewed in FIG. 2, the collars 124 of the toggle arrangements 108 are moved toward the end plate 14, as seen in FIG. 3, causing the die gates 86 and 88 to close due to the lateral force exerted thereon by the piston rods through the toggle arms 118.

The die part 82, which is sometimes called a coining ring, has a horizontal bore 155 therethrough which is coaxial with and slidably receives the tube. The ring 82 includes a cylindrical boss 156 which extends toward the annular flange 105 of the die. The outer diameter of the boss 156 is dimensioned so as to permit sliding motion of the ring 82 toward the annular flange 105 even when the die gates 86 and 88 are closed that is, in the position as illustrated in FIG. 10, for example.

It can be appreciated that the inner surface 105' of flange 105 and the bore 155 in the coining ring 82 define the bore 33 passing through die 34. In addition, the annular wall 158 on the end of the boss 156, the annular wall 160 of the flange 105, and the continuous cylindrical surface 103 provided by the arcuate surfaces 98 and 100 when the die gates are closed, define the annular channel 35 in the die 34.

It is an important feature of the invention that the die 34 be divided into the two basic parts 82 and 84, so that the annular walls 158 and 160 of the channel 35 are movable axially relative to one another. As a consequence, an axial force may be applied individually to each convolution 81 to crimp the outer edge thereof immediately after the formation of the convolution within the channel 35, as will be described in detail later in connection with the description of the over-all operation of the apparatus.

The annular walls 158 and 160 preferably are shaped to provide matching annular corrugations so that the annular walls of a convolution 81 which is crimped by moving wall 158 toward wall 160, will have corrugations which nest or lie flush against the annular walls of adjacent convolutions. Such corrugations are desirable in order to eliminate what is referred to in the art as oil-canning, which is the noise that occurs during axial compaction ofa stacked bellows, such noise being similar to that heard when pressing the bottom of an oil can.

The annular wall 162 of the flange 105 has a configuration conforming to that of the annular wall 158 so that a convolution formed and crimped by the die 34 and moved to the right-hand side of the flange 105 will lie flush against the annular surface 162. By this arrangement, the axial spacing between adjacent convolutions of a bellows formed by the apparatus will be maintained at a minimum.

In order to apply an axial force to the coining ring 82 in the direction of the die part 84, there is provided preferably a hydraulic cylinder 164 which is fixedly secured to the end plate 16. The piston rod 166 of the cylinder 164 is connected through a U-joint 166a to a rod l66b. The rod 16611 is threaded into a collar 167. The collar is rotatably mounted on a pin 168 which is connected to the lower end of a pair of vertical arms 170 and 172, as best seen in FIGS. 4 and 5. The upper ends of the arms 170 and 172 are pivotally mounted by means of a horizontal pin 174 journalled in spaced flanges 176 and 178 ofa support 179 bolted to the end plate 14. A pair of brackets 180 and 182 are fixed to the rear surface 188 of the coining ring 82. Horizontal pins 184 and 186 fixedly mounted in the arms and 172, respectively, are loosely positioned in horizontal bores 185 and 187 in the brackets. When the hydraulic cylinder 164 is actuated to shift the piston rod 166 in the rightward direction as viewed in FIG. 4, the arms 170 and 172 will pivot about the pin 174, forcing the pins 184 and 186 against the brackets and 182, thus causing the coining ring to be forced into the die part 84. Because of the loose mounting of pins 184 and 186 in the bracket bores and 187, respectively, the coining ring is allowed to self-adjust when entering the die part 84.

In order to selectively control the width of a convolution crimped in the channel 35 by the coining ring, there is provided a rod 189 threaded into the end plate 14. A lock nut 189a is threaded onto one end of the rod. The other end of the rod 189 is positioned to engage a stop 18% on the collar 167. The axial position of rod 189 determines the extent of movement of the coining ring in the rightward direction as viewed in FIG. 4 and consequently, the extent of movement of the wall 158 toward the wall 160 when the cylinder 184 is actuated to crimp a convolution. As is apparent, by changing the axial position of the rod 189, the operator may vary the width ofa convolution crimped in the die by the coining ring.

One can appreciate that the distance between the walls 158 and 160 of the die parts could be adjusted and, thus, the width ofa convolution formed in the die by compression of the resilient element 80 could be controlled by positioning an adjustable stop (not shown) behind the arms 170 and 172.

The apparatus 10 also includes a mechanism, generally designated 192, for sequentially advancing the tube 66 in the direction of the die 34, so that after one convolution ofa bellows is formed in the tube 66, the tube may be shifted to move the convolution outside of the die and to bring additional tube material into position for forming the next convolution. The tube advancing mechanism 192 comprises a carriage, generally designated 194, and a drive member, generally designated 196.

The carriage 194 includes horizontal cross arms 198 and 200 which are slidably mounted at their ends on posts 128 and 134. Two elongated members 202 and 204 which extend parallel to the longitudinal axis of the shaft 32 are positioned below the cross arms 198 and 200 and are secured thereto by vertical elements 206, 208, 210 and 212. A pneumatic cylinder 214 is secured to the end plate 16 and has its piston rod 216 connected to the cross arm 198 of the carriage by a nut 217, so that the carriage including the elongated members 202 and 204 may be shifted toward and away from the die 34. The opposed faces of the elongated members 202 and 204 are formed with one-way clutch teeth 218 and 220, respectively, which are engaged by dogs 222 and 224 carried by the drive member 196.

The drive member 196 has a central bore 226 receiving the shaft 32 so that the drive member may slide axially along the surface of the shaft. As best seen in FIG. 7, the drive member includes two plates 232 and 234 which are secured together by bolts, not shown. The plate 232 includes a downwardly extending arm 233 with a horizontal bore 235 therethrough which slidably receives a horizontal rod 236. The rod 236 is parallel to the shaft 32 and is fixed to the end plate 16. The rod 236 provides a guide for the drive member 196, insuring that it is properly positioned so that the dogs 222 and 224 engage the clutch teeth 218 and 220. The plate 232 has a forward annular extension 228 which abuts against the end 230 of the tube 66 so that the tube is moved axially upon the axial movement of the drive member toward the die 34.

The plate 234 includes cutout portions 237 and 239 in its side so as to provide channels for two L-shaped arms 238 and 240 which are mounted for vertical pivotable movement about pins 242 and 244, respectively, fixed to plate 232. The shorter legs of the L- shaped arms 238 and 240 are shaped to provide the dogs 224 and 222, respectively. A spring 246 is mounted in a bore 248 in the plate 234 and bears against the edge 249 of the arm 238, urging the dog 224 outwardly into engagement with one of the clutch teeth 220 on the elongated member 204. Another spring 252 is mounted in a bore 254 in the plate 234 and bears against the edge 255 of the arm 240 so as to force the dog 222 outwardly into engagement with one of the clutch teeth 218 on the member 202. As seen in FIG. 7, the dogs 224 and' 222 engage the lateral edges 255 and 256, respectively, of the clutch teeth 220 and 218.

As is apparent, movement of the carriage 194, and hence the members 202 and 204 in the rightward direction as viewed in FIG. 7, will result in the drive member 196 and, thus, the tube 66, being shifted in the same direction. Movement of the members 202 and 204 in the reverse direction, however, normally does not cause the drive member 196 to be shifted away from the die, since the spring biased dogs 222 and 224 are forced inwardly due to the cam action of the inclined edges 257 and 258 of the clutch teeth 218 and 220, respectively, upon the dogs.

An actuating arm 259 for manually disengaging the dogs 222 and 224 from the clutch teeth is pivotally mounted to the face of the plate 234 by means of a pin 260. The actuating arm 259 carries two pins 262 and 264. A link 266 is pivotally mounted at one end to the pin 264. An elongated slot 268 is formed in the other end of the link 266. A pin 270 at the end of the arm 238 is slidably engaged in the slot 268. A second link 272 is pivotally mounted at one end to the pin 262 carried by the actuating arm 259, and has a slot 274 at its other end in which a pin 276 on the end of the arm 240 is slidably engaged.

It can be seen that by exerting a clockwise force, as viewed in FIG. 7a,-upon the end 278 of the actuating arm 259, the arm 238 will be pivoted in a counterclockwise direction about the pin 242, while the arm 240 will be pivoted in a clockwise direction about the pin 244. This results in the two dogs 224 and 222 being retracted within the periphery of the annular plates 232 and 234, thus disengaging the dogs from the clutch teeth 220 and 218. Consequently, by this arrangement, an operator may manually retract the dogs 222 and 224 at any time in order to shift the drive member 196 in a direction away from the die 34.

The mechanism 192 for sequentially advancing the tube 66 toward the die 34 is operated by actuating the pneumatic cylinder 214 to move the carriage 194 in the rightward direction, thus moving the drive member 196 and, hence, the tube in the same direction into the die 34.

In order to control the distance of movement of the tube 66 by the drive member 196, there is provided a horizontally extending rod 280 which is threaded in an opening 282 in the end plate 14 of the apparatus. The rod is secured to plate 14 by means of a lock nut 284. The forward end 286 of the rod 280 provides a stop which engages an element 288 carried by the cross arm 200 of the carriage 194 so that the extent of movement of the carriage in the rightward direction is limited by the position of the rod 280. By changing the axial position of rod 280, the operator may selectively adjust the distance of movement of the carriage 194 and, therefore, the distance of movement of the drive member 196 toward the die 34. Consequently, the amount of tube 66 which is fed to the die 34 can be controlled by adjustment of the rod 280.

After the carriage 194 is moved in the rightward direction, to feed the tube 66 to the die 34, the fluid cylinder 214 is reversed to cause the carriage 194 to return to its original position. As can be appreciated, with each reciprocation of the carriage 194 toward and away from the die 34, the drive member 196 for the tube 66 is sequentially shifted along the carriage 194 toward the die until the drive member reaches the end of the carraige. At that time, the dogs 222 and 224 are manually retracted in the manner described previously so that the drive member 196 may be moved in a leftward direction viewed in FIG. 2, thus permitting a new tube 66 to be mounted in the apparatus for forming into a bellows.

It is possible that when the carriage 194 moves in a direction away from the die 34 during the reciprocation of the carriage, the drive member will move in the same direction due to the axial component of force resulting from the engagement of the dogs 222 and 224 by the inclined edges 257 and 258 of the clutch teeth. Hence, it is desirable to provide means for holding the drive member 196 firmly against the shaft 32 to insure that the drive member remains in abutting engagement with the end 230 of the tube 66 during movement of the carriage 194 away from the die. Such a holding means, generally designated 294, is illustrated in FIG. 7a.

The holding means 294 includes a bore 296 formed in the downwardly extending arm 233 of the plate 232. A piston 298 is slidable within the bore. An opening 300 in the arm 233 communicates between the bore 296 and a fitting 302 which is connected to a source of actuating fluid, not shown. The piston 298 has an upwardly extending rod 304 slidable within a bore 306 in the plate 232. The bore 306 extends from the bore 226 to the bore 296. A friction element 307, such as a circular piece of leather, is positioned between the surface of the shaft 32 and the end 308 of the rod 304. One can see that by forcing fluid through the fitting 302 into the bore 296, the piston 298 and rod 304 are moved upwardly to compress the friction element 307 against the shaft 32, thus functioning as a brake to hold the drive member 196 against the shaft.

A modified form of a drive means 310 for the tube advancing mechanism 192 is illustrated in FIGS. 8a, 8b and 8c. Such mechanism is bolted to the elongated member 202 and 204 of the carriage 194 by brackets 311 and 312, respectively. Hence, the drive means 310 is fixedly connected through brackets 311 and 312 and carraige 194 to the piston rod 216 of cylinder 214, in contrast to drive member 196 which is connected to the piston rod 216 through the clutch mechanism in- 1 1 cluding the dogs 222 and 224 and clutch teeth 218 and 220.

The drive means 310 includes a gripping ring 313 which surrounds the tube 66. The ring 313 includes tow semicircular sections 314 and 315 pivotally connected together at one side by a horizontal pin 316. The other side of the ring sections 314 and 315 are biased apart by a spring 317. Arcuate segments 318 and 319 of suitable friction material, such as Micarta, line the inner surfaces of the ring sections 314 and 315, respectively. A pneumatic cylinder 320 is fixedly mounted to the bracket 311 by a vertical support 321. The piston rod 322 of the cylinder is arranged to engage an upwardly facing shoulder 323 on the free end of the ring section 314. When the cylinder 320 is actuated, the piston rod 322 forces the ring section 314 into frictional engagement with the surface of tube 66 so that the tube is firmly clamped by the gripping ring 313. The clamping of the tube 66 by ring 313 is released by spring 317 when pneumatic pressure in the cylinder is relieved.

In operation of the tube advancing mechanism 192 employing drive means 310, if the wall of the tube 66 is relatively heavy, the cylinder 320 of the drive means is continuously actuated so that the gripping ring frictionally engages tube 66 during the entire operation of the apparatus. The piston rod 216 of the cylinder 214 is moved in the rightward direction as viewed in FIG. 8b, after a convolution has been formed in the tube 66 and the die gates have been opened. This causes the tube 66 to be shifted in the same direction due to the frictional engagement between the tube and the gripping ring 313. The cylinder 214 is actuated to move the piston rod 216 in the reverse direction that is, away from the die 34 when the shaft 32 is moved toward the die by the hydraulic cylinder 22. At this time, a convolution in the tube 66 is being formed by the compressed resilient element 80, thereby holding the tube axially in place. Hence, the gripping ring 313 of the drive means 310 will slide on the stationary tube 66 in a leftward direction as viewed in FIG. 8b, to its original starting position without shifting the tube in the same direction. If the wall of the tube 66 is relatively thin, pressure in the cylinder 320 should be relieved when cylinder 214 is reversed in order to release the clamping of the tube 66 by gripping ring 313. It can be appreciated that the modified drive means 310 is somewhat simpler and less expensive than the drive member 196 which requires the clutch teeth on the elongated members 202 and 204 of the carriage 194 for operation. However, the drive member 196 is preferred when relatively large bellows are being formed.

OPERATION OF THE APPARATUS The over-all operation of the apparatus 10 employing drive member 196 is as follows: the frame 38 is disengaged from the end plate 14. The tube 66 is slid onto the shaft 32 with a portion of the tube extending beyond the side of the die 34 which faces the frame. The rubber element 80 is then positioned within the tube 66 and the shaft 36 is slid into the tube until the end of the shaft 32 and the end of the shaft 36 abut the rubber element 80 as seen in FIG. 9. The frame 38 is then fixed to the end plate 14 by means of the bayonet locking elements 68 and 70, so that the shaft 36 connected to the frame 38 provides a fixed end wall against which the rubber element 80 may be compressed.

The die gates 86 and 88 are then closed by operating the pneumatic cylinders 136 and 138 so that the parts of the die 34 are in the position as illustrated in FIG. 10.

After the gates 86 and 88 of the die are closed, the hydraulic cylinder 22 is actuated to move the shaft 32 in the rightward direction. This causes an axial, compressive force to be exerted upon the rubber element which forces the element radially against the wall of the tube 66, thereby forming the wall into a convolution 81, having a generally arcuate outer edge, as seen in FIG. 11. At substantially the same time, the cylinder 214 is actuated to shift the carriage 194 away from the die. At the same time, the holding device 294 for the drive member 196 is actuated to insure that the drive member does not shift away from the tube 66. The shaft 32 is then shifted away from the shaft 36 by the cylinder 22 so as to relieve the axial pressure upon the rubber element 80, thereby permitting the element to return to its original configuration as seen in FIG. 12. Hence, after the convolution forming step, there remains no rubber material within the convolution. Next, the coining ring 82 is moved toward the annular wall 160 of flange by actuating the hydraulic cylinder 164, thereby crimping the outer edge of the convolution 81 as seen in FIG. 13.

After the convolution has been crimped, the coining ring 82 is moved away from the other part 84 of the die by the hydraulic cylinder 164. At the same time, the die gates 86 and 88 are opened by actuating the cylinders 136 and 138. The gates are opened a sufficient distance to permit movement of the crimped convolution therebetween. The cylinder 214 is then actuated to move the carriage 194 in the rightward direction as seen in FIG. 14, thereby shifting the tube 66 to a position so that the crimped convolution 81 will engage the back annular wall 162 of the flange 105 when the die gates are closed. Thereafter, the die gates are shifted by the cylinders 136 and 138 to their closed position, as seen in FIG. 15.

With the tube 66 and parts of the die 34 in the position shown in FIG. 15, the above described sequence of steps are repeated to form additional crimped convolutions in the tube.

When the driving member 196 of the tube advancing mechanism 192 reaches the forward end of the carriage 194 adjacent to the die 34, the sequence of operations described above are stopped, which permits the operator to release the dogs 222 and 224 from the clutch teeth 218 and 220. The drive member 196 may then be shifted to the rear end of the carriage 194. The frame 38 is then released from the end plate 14 and the tube 66 withdrawn from the shaft 36. The unformed cylindrical portion of tube 66 is cut off at the desired point, leaving the formed portion which constitutes the bellows 328 seen in FIG. 16. Alternatively, the tube may be reversed in the apparatus, with the bellows supported by shaft 36 of the frame, and the unformed portion of the tube supported by shaft 32 in position for having convolutions formed therein.

It is to be understood that the cylinders 22, 136, 138, 164 and 214 may be actuated so as to perform the steps of the method of the invention in the sequence described above by any suitable fluid, electro-mechanical or electronic control system, which is understood in the art. By the use of an approriate electromechanical control system, a convolution has been formed and crimped in the apparatus 10 within about 3 seconds.

Consequently, the apparatus is capable of very rapidly forming the bellows 328 having a series of convolutions with crimped outer edges.

An important feature of the invention is that the method and apparatus permit a crimping operation to be performed on each individual convolution of a bellows as it is formed within the die 34. Hence, sharp outer edges may be formed in the crimped convolutions of the bellows by an additional compressing operation which is not possible if one were to compress a conventional formed bellows having a plurality of convolutions with rounded outer edges, due to the peripheral material between the annualr walls of the convolutions.

After the bellows 328 is withdrawn from the apparatus 10, the inner diameter or edges of the convolutions 81 are sharp-rolled. As shown schematically in FIG. 17, this sharp rolling step is accomplished in a conventional manner by positioning the bellows over a rotating shaft 330 having a plurality of V-shaped convolutions 331 therein with sharp valleys 332. A rotating sharp wheel 334 mounted on a shaft 336 is urged laterally toward the shaft 330 between the annular walls of a convolution of the bellows. The shaft 330 and wheel 334 rotate in opposite directions, thereby rotating the bellows 328 about its own longitudinal axis and sharpening the inner periphery ofa convolution of the bellows. Thereafter, the rotating wheel 338 is moved laterally away from the bellows to permit the bellows to be shifted in the rightward direction as viewed in FIG. 17, so that the inner peripheries of the remaining convolutions of the bellows may be consecutively formed with sharp edges.

After all of the convolutions in the bellows 328 are provided with sharp inner edges, the bellows is compressed axially. This is accomplished, as shown schematically in FIG. 18, by positioning the bellows between a stationary. ring 338 and a movable ring 340. Ring 340 is urged toward ring 338, thereby compressing the convolutions so that the bellows will have the configuration illustrated in FIG. 19. Such bellows is the final desired product of the invention, having all the physical characteristics of a conventional stacked bellows, namely, sharp inner and outer edges 342 and 344, respectively, yet formed from a single metal tube. The bellows is free of the disadvantages resulting from the use of annular welds or solder joints in manufacturing conventional stacked bellows, yet is produced more 'rapidly and at substantially less expense.

Due to the number of forming operations on the metal tube 16 in producing the bellows 328 of the invention, it is desirable to stress relieve the bellows by heat treating in a conventional manner.

Although the invention has been herein described and shown in what is conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein, but is to be accorded the full scope of the claims so as to embrace any and all similar and equivalent structures, products and methods.

What is claimed is:

1. An apparatus for use in manufacturing from a metal tube a stacked seamless bellows having a plurality of convolutions with crimped generally sharp outer edges comprising:

means for sequentially advancing a tube a predetermined distance along its longitudinal axis;

a die having a bore therethrough coaxial with the longitudinal axis of said tube and adapted to receive said tube therein, an annular channel in said die opening into the wall of said bore, said channel having first and second annular walls;

means adapted to be positioned within the tube for exerting sufficient lateral force on the wall thereof to force a portion of the wall into said channel to form a convolution in said tube;

said die being formed of two parts, one of said parts including said first annular wall of said channel and the other of said parts including said second annular wall of said channel;

means for moving one of said parts axially toward the other of said parts to crimp the convolution therebetween to bring the walls of the convolution into relatively close axial proximity and produce a relatively sharp external ridge;

the one of said two parts on the side of the direction of movement of the tube by said sequentially advancing means being divided into two sections separable transversely of the axis of said channel;

means for moving said two sections apart a distance sufficient to permit passage of a crimped convolution therebetween prior to sequential advancement of the tube and for moving said parts together after sequential advancement of the tube;

said sequential advancing means comprising,

a drive member mounted coaxially with the longitudinal axis of the bore in said die and adapted to abut the end of said tube;

said drive member carrying an element at its side biased outwardly from said member;

a carriage having an elongated member spaced from but parallel to the longitudinal axis of said drive member;

said elongated member having a series of one-way clutch teeth therein arranged to drive said drive member through said biased element when said carriage is moved toward said die and to permit movement of said carriage past said element in the reverse direction of movement of said carriage; and

means for moving said carriage sequentially toward and away from said die a predetermined distance.

2. A method of forming a metal tube into a bellows comprising the steps of forming in the wall of said tube a circumferential convolution having sides extending radially of said tube, crimping the sides of said convolution toward each other and into a configuration in which directly opposed side walls of a convolution are compressed into complementary nestable walls which are parallel and curvilinear in cross-section and present a sharp outer edge, sequentially thereafter forming a second such convolution adjacent said first convolution and crimping the same into a corresponding configuration, circumferentially indenting a portion of the wall of said tube between said crimped convolutions into a configuration presenting a sharp trough between said convolutions, and thereafter axially compressing the wall of said tube between said convolutions to decrease the spacing between the adjacent sides of adjacent convolutions.

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1. An apparatus for use in manufacturing from a metal tube a stacked seamless bellows having a plurality of convolutions with crimped generally sharp outer edges comprising: means for sequentially advancing a tube a predetermined distance along its longitudinal axis; a die having a bore therethrough coaxial with the longitudinal axis of said tube and adapted to receive said tube therein, an annular channel in said die opening into the wall of said bore, said channel having first and second annular walls; means adapted to be positioned within the tube for exerting sufficient lateral force on the wall thereof to force a portion of the wall into said channel to form a convolution in said tube; said die being formed of two parts, one of said parts including said first annular wall of said channel and the other of said parts including said second annular wall of said channel; means for moving one of said parts axially toward the other of said parts to crimp the convolution therebetween to bring the walls of the convolution into relatively close axial proximity and produce a relatively sharp external ridge; the one of said two parts on the side of the direction of movement of the tube by said sequentially advancing means being divided into two sections separable transversely of the axis of said channel; means for moving said two sections apart a distance sufficient to permit passage of a crimped convolution therebetween prior to sequential advancement of the tube and for moving said parts together after sequential advancement of the tube; said sequential advancing means comprising, a drive member mounted coaxially with the longitudinal axis of the bore in said die and adapted to abut the end of said tube; said drive member carrying an element at its side biased outwardly from said member; a carriage having an elongated member spaced from but parallel to the longitudinal axis of said drive member; said elongated member having a series of one-way clutch teeth therein arranged to drive said drive member through said biased element when said carriage is moved toward said die and to permit movement of said carriage past said element in the reverse direction of movement of said carriage; and means for moving said carriage sequentially toward aNd away from said die a predetermined distance.
 2. A method of forming a metal tube into a bellows comprising the steps of forming in the wall of said tube a circumferential convolution having sides extending radially of said tube, crimping the sides of said convolution toward each other and into a configuration in which directly opposed side walls of a convolution are compressed into complementary nestable walls which are parallel and curvilinear in cross-section and present a sharp outer edge, sequentially thereafter forming a second such convolution adjacent said first convolution and crimping the same into a corresponding configuration, circumferentially indenting a portion of the wall of said tube between said crimped convolutions into a configuration presenting a sharp trough between said convolutions, and thereafter axially compressing the wall of said tube between said convolutions to decrease the spacing between the adjacent sides of adjacent convolutions. 